Sludge dewatering process of polyacrylamide
In sewage treatment, the two main role of polyacrylamide is flocculation and sludge dehydration, polyacrylamide can be divided into anions, cations, amphoteric ions and non-ionic types, different types of polyacrylamide in the application is also very different.
It is very important to choose suitable flocculant in sludge dewatering. The selection of polyacrylamide flocculant should be based on the principle of high efficiency and less dosage. Generally speaking, organic sludge is suitable to add cationic flocculant, and inorganic sludge should be added anionic flocculant. Municipal sludge is mainly organic sludge, and has a certain amount of negative charge, so the selection of cationic flocculant. In theory, the higher the molecular weight of polyacrylamide flocculant, the higher the flocculation efficiency of polyacrylamide, and in practice, the charge quality of cationic flocculant determines the correctness of sludge selection, the higher the ionic degree, the more expensive the price. In practical application, the molecular weight of flocculant is generally about 10 million.
Polyacrylamide concentration and the use of the relationship: When the polyacrylamide concentration is 0.2%, the temperature is 25~30 degrees, for the mechanical sludge, suitable polyacrylamide ionic degree 55%~60%, molecular weight 15 million cationic organic polymer polyacrylamide, dosage is 100g/m3, dehydration rate is 69%~74%, 49%~50%; For the sludge of municipal sewage treatment plant, the suitable flocculant is cationic organic polymer polyacrylamide with ionic degree of 60%~100% and molecular weight of 3 ~6 million. The dosage is 100g/m3 and the dehydration rate is 79%. The flocculant suitable for rubber processing sludge is a variety of cationic flocculant, dehydration rate is 55%~63%, anionic flocculant effect is also better, but the amount is more.
The appropriate dosage of polyacrylamide flocculant is that all the flocculants are adsorbed on the surface of solid particles, and the sedimentation rate of the flocculant reaches a maximum value. But to find out the suitable flocculant dosage is very difficult, in order to get drugs using value through sewage treatment technology professionals for precise reagent selection, combined with practical application and draw lessons from past practice case, general mills, dye factory with weak cationic flocculant, and sewage treatment plants generally selected strong cationic polyacrylamide, Like pharmaceutical factories, tanneries to use strong cationic polyacrylamide can be treated.